Hi all,
I'm having some issues (some possibly mine, some possibly tksurfer's) getting tksurfer (5.3c6) to display curvature the way I think it should be able to. I am using the bert sample data.
The Curvature display --------------------- If I use the Show Curvature button in the UI control panel, I get the familiar gyrus=green; sulcus=red pattern applied to the displayed brain.
The Configure Curvature Display is a bit of a shambles, and I think should be fixed. First, it is virtually impossible to set midpoint using the slider, because the values it pushes to the adjacent textbox are way too coarse. Typing values into the midpoint textbox works, in that it affects the balance of red and green in the display. However the textbox does not affect the position of the slider, suggesting that it actually does not work.
That said, there's no actual adjustment of the threshold size. Indeed, it's not clear that there actually IS a threshold -- perhaps there isn't. Maybe "threshold midpoint" just sets the midpoint of the color range?
And then there's a a textbox labeled "threshold slope". I'm pretty sure that's nonsensical phrase. What this box appears to do is set the ratio of color to curvature value. Ie: "Color intensity".
Bottom line -- this dialog only partially fits the purpose at hand, and is so confusingly wording that ones attempts to use it are pretty much random. It may even be that some UI elements or functionality that was once there has gone missing accidentally?
Finally, I wanted a colorbar for the curvature display, and so far as I can tell there isn't one. I can turn on a colorbar, but it's the one for overlays.
Using a Curvature variable as an overlay ---------------------------------------- I next tried to read in the k1.crv variable as an overlay. This sort of works, but gives a very mottled display (except using "heat map" color scheme), I think because even in definite sulcus and gyrus regions, the curvature values straddle the border of the grey range of color, and I'm not sure how to adjust it sensibly.
-- I couldn't figure out how to set the overall color range, that is to say the extremes of the colorbar. These seem stubbornly stuck at 5.0 and -5.0. In particular, the Theshhold Max setting doesn't seem to affect the extremes of the color range.
-- I couldn't figure out how to eliminate the large grey range in the middle of the color range. I noted that the Threshhold Min setting can be used to make the grey range larger, but setting Min below 1.5 (for example, zero) does not eliminate the grey between 0 and +/-1.5.
------------------------
Anybody have any helpful clues on these items!
Thanks!
-- Graham